# -*- coding: utf-8 -*-
"""
Created on Thu Sep 19 10:53:56 2019

@author: Administrator
"""

# 1023 组个最小数
# 通过所给数字，按照以非减小的顺序进行排列
# 因为首位不能为零，当存在零时，交换零组与相邻第一个元素交换
"""
def test():
    raw = str(input()).split(' ')
    
    result = ''
    for index in range(1,len(raw)):
        digit_count = int(raw[index])
        temp = str(index) * digit_count
        result = result + temp
    
    if raw[0] != 0:
        result_list = list(result)
        result_list.insert(1, '0' * int(raw[0]))
    
    print(''.join(result_list))
    
test()
"""